Moistureproof article



Patented use, 1931 MOISTUREPROOF ARTICLE William Hale Charch, Buffalo, N. Y., and Merlin Martin Brnbaker and Frederick M. Meigs, Wilmington, Del., assignors, by mesne assignments, to E. I. du Pont de' Nemours & Company, Wilmington, Del., a corporation of Delaware No Drawing. Application December 21, 1934, Serial No. 758,654

14 Claims.

- This invention relates to the art of moistureproofing. More particularly, it relates to a composition of matter suitable for the production of moistureproof materials and also to the moistureproof materials per so.

We believe that moistureproofing is due to (l) the use of an agent which is inherently moistureproof, and (2) the laying down of this agent in a continuous unbroken film, either alone or in combination with other materials or vehicles hereinafter called film-forming substances. 7

We have found, as a result of a large number of experiments, that substances are inherently moistureproof when they are of such a nature that they are not only insoluble in water but also dissolve none or at least only an infinitesimal amount. of-'water. -Apparently, water vapor diffuses through continuous unbroken films of such substances by a process of dissolving in the film .and evaporating from the other side. The solubility of water in the moistureproofing agent largely determines the rate of transfusion of water vapor through the mm, and therefore its inherent moistureproofness. Obviously, if the film is noncontinuous and broken, other factors enter into a the determination of the degree of mcistureproofness.

We have found that organic ethers of the type hereafter more fullydescrlbed can be used in the preparation of molstureproofing compositions which will yield molstureproof films, i. e. coatings or self-sustaining films which are preferably also transparent, glossy, non-tacky, flexible, possess good surface slip, etc.

For the purposes of this specification and claims, we define moistureproof materials as those which, in the form of continuous unbroken sheets or film, permit the passage of not more than '10 grams of water vapor per 100 square meters per hour, over a period of 24 hours, at approximately 35 C.i0.2 0., the relative humidity of theaatoneside ofthefihnbeingmaintainedatleastat 98% and the relative humidity nftheatnnsphereattheothersidebeingmaintainedatsuehnvalueastogiveahumiditydifierentiflofnthfifik mnimmthenhidmintheform damnnbrolmmnappliedunimiaeoatincwifliatotfleootinzthickness For the purpose of experimental tests, especially 5 for those materials adaptable as coating compositions, moistureproof -materials include those Silhstances, compounds or compositions which, when laid down in the form of a continuous \mbroken film applied uniformly as a coating with a total 10 coating thickness not exceeding 0.0005" to both sides of a sheet of regenerated cellulose of thickness approximately 0.0009", will produce a coated 'sheet which will permit the passage therethrough of not more than 570 grams of water vapor per 100 square meters per hour over a period of approximately 24 hours, at a temperature of 35 C.:0.2 C., with a water vaporpressure differential of 40-44 mm. (preferably i1.8:0."lmm.)

of mercury. For convenience, the niunber of grams of water vapor passed under these condi tions may be referred to as the permeability value. An uncoated sheet of regenerated cellulose having a thickness of approximately 0.0009" will show a permeability value of the order of 25 5700.

From the foregoing, it is apparent that under the conditions set forth, a moistureproofed regenerated cellulose sheet is capable of, the passage of moisture or water vapor at least 10 times as effectively as regenerated cellulose sheet.

We have'specifically defined herein moistureproofness in terms of a permeabiliio test performed at substantially C. It is to be under- 35 stood, however, that by the adoption of this condition no disclaimer is madeoi molstureproofness of any of the materials or compodtions when tested at temperatures lower than 35 C. Likewlse,nodisclaimerismadeo!flng effectsexhibited by the materlalsherdn V at temperatures above 35 C. Bren: will be a tem- 3 theuncoated,

qualitythematu'ialshereindescribedasmdsagmtr. Theerltiealtemperatumabove'which these mnolongerexlubltproperthese substituent groups. ification is concerned, a hydrocarbon carbon atom ties is dependent primarily upon the melting point of the material and upon the nature and composition of the film-forming substance with which it is used. Agents of higher melting points will show moistureproof properties up to higher temperatures than will agents of low melting points, other conditions being equal. Generally speaking, the agents of higher melting points will be preferred for this reason, though for certain other purposes it may be definitely advisable to use agents of lower melting points.

It is, therefore, an object of this invention to provide a composition of matter suitable for easting or coating purposes comprising a film-forming substance and an organic ether, more fully described hereafter, which will deposit a moistureproof film, i. e. a self-sustaining film or coating which is preferably also transparent, fiexible, non-tacky, glossy and possesses good surface slip.

Another object of this invention is to provide moistureproof films, i. e. self-sustaining films or coatings containing organic ether which imparts moistureproofness thereto, said films being preferably also transparent, flexible, non-tacky, glossy and possessing good surface slip.

'Other objects will become apparent from the following description and appended claims.

The instant invention, in one phase thereof,

contemplates a flowable composition of matter of at least 3 7 C. The molecule of the moistureproof mono-ethers is largely hydrocarbon carbon, but may contain the usual modifying groups, such as hydroxyl, carbonyl, halogen, ester, etc., providing it has a sufliciently high hydrocarbon carbon content to oflset the amnity for water for is one which has at least three of its valences'attached to carbon or hydrogen.

When an organic mono-ether containing no modifying group in the molecule is used as the moistureproofing agent, we have found that the molecule must contain at least 18 hydrocarbon carbon atoms in the hydrocarbon portion thereof for the ether oxygen group (-0) in order to achieve a moistureproofing effect. When more than 18 hydrocarbon carbon atoms are present, better moistureproofing efiects are secured.

- The organic mono-ethers contemplated by the I instant invention may be aliphatic or aromatic or mixed aliphatic aromatic, cyclic or substituted mono-ethers containing additional active or modifying groups. Any group or atom other than hydrocarbon is considered an active group. We have found that, when the number of active groups is increased, for example, when two similar active groups are present, the limiting ratio may be 55%-66% of the'limiting ratio for one such group, while for three similar active groups the limiting ratio is 45 %-55% and approaches a limiting value of 30% as the number of-simi- Insofar as this spec-.

lar active groups is further increased. when different active groups are introduced, the limiting ratio of hydrocarbon carbon atoms will vary, depending on the nature and number of such groups. Thus, for example, if two different active groups are present, the limiting ratio of hydrocarbon carbonatoms to active groups will be 55%-66% of the mean of the limiting ratios for each .of the individual active groups.

Dicetyl ether, di-octadecyl ether, beta-naphthyl octadecyl ether, phenyl lignoceryl ether, etc. are specific illustrative examples of organic ethers which are moistureproof and can be utilized in the preparation of moistureproof films.

At previously mentioned, the composition also contains a film-forming substance. As illustra- I tive examples of film-forming substances may be mentioned cellulose derivatives, for example, 'cellulose nitrate, cellulose acetate, ethyl cellulose, benzyl cellulose, mixed esters or ether esters; resins, either natural or synthetic, such as rosin, hydrogenated rosin and its derivatives, including glycerol, glycol or diethylene glycol esters of hydrogenated rosin; rosin esters of gycerol, glycol or diethylene glycol; gum dammar; polybasic acid-polyhydric alcohol resins, either modified or unmodified; vinyl resins of the polymerized vinyl acetate, polymerized chlor-vinyl acetate and polymerized vinyl acetal resin types; metastyrene resin; phenolic condensation products; rubber, gutta percha, balata, caoutchouc; synthetic rubbers including polymers of isoprene, butadiene and their homologues; chemical derivatives of rubber, such as halogenated rubber, rubber treated with sulphuric acid, rubber treated with tin tetrachloride; rubber treated with chlorostannic acid; varnishes; etc. One or a plurality of film-forming ingredients may be used. The precise film-forming ingredient or mixture thereof depends upon the purpose for which the com positions are to be used.

When the composition contains a softener, any

suitable softener for the film-forming ingredient may be used. For example, diamyl phthalate, tricresyl phosphate, dicyclo-hexyl phthalate, butyl benzoyl benzoate, etc. may be used, when the film-forming ingredient is a cellulose derivative.

In some compositions wherein a cellulose derivative is used. the film which is produced may be hazy. If desired, this may, be overcome by incorporating in such a composition a blending agent. Such compositions also are generally more moistureproof than those without the blending agent or gum. 'I'he blending agent tends to improve the compatibility of the moistureproofing agents with the other ingredients in the film and consequently the impermeability of the film. As several illustrative examples of blending agents may be mentioned gums or resins,

such as dammar, gum elemi, ester gum, hydrogenated rosin; hydrogenated ester gum or the like, halogenated diphenyl, a naturaloccur-ring balsam or a synthetic balsam-like substance, such as diethylene glycol hydrorosinate or a substance such as lanum, hydrogenated castor oil, di-dodecyl phthalate, retene, diricinoleic ester of glycerol or the like.

r The ingredients which constitute the final film may be dissolved in an appropriate solvent or solvent mixture to form a solution which may beused as herein described. Alternatively, the ingredients constituting the final film may be used in theform of a melt. When the composition is to be used in the form of a melt, it is desirable amass 3 to include therein a blending agent to inhibit crystallization. Hydrogenated rubber, hydrogenated ester gum, rosin, dammar, dlethylene glycol hydrorosinate and the like, are several 5 illustrative examples of crystallization inhibitors. Whenever the composition is in the form of a lacquer and used for coating purposes, the solvents thereof are chosen so that they will not produce any deleterious eflects on the base being 10 coated.

The proper formulation of the lacquer so that it will yield coatings which are transparent and "highly moistureproof is determined by tests.

One of the most important things to be deter- 15 mined isthe proper amount of blending agent to be used. This can be determined, for example,.

as follows: A series of compositions is prepared containing the same amounts of lacquer base, softener, moistureprooilng agent and solvent. 20 Diiferent quantities of blending agen are then added to each of these lacquers and the general properties, such as transparency and the permeability values of sheets of regenerated cellu lose, for example, coated with each of these com- 25 positions, are plotted against the ratio of blending agent to moistureproofing agent used.

When a lacquer 'of the type described in Example IV is modified according to this systematic procedure, it will be found that the lowest 30 permeability value occurs very near the point where the coatings become completely transparent. In the case of di-octadecyl ether in this particular compositon, this point is equivalent to approximately 3.25 to 6 grams of dammar to 35 1 gram of di-octadecyl ether. It is obvious that this optimum blending agent-moistureprooflng agent ratio will vary for different moistureproof-' ing agents and for different blending agents with the same moistureprooflng agent. In general,

45) this ratio depends upon the hydrocarbon carbon content and the solubility of the moistureproofing agent in the lacquer solids. Thus, the ratio is high for moistureprooflng agents having high hydrocarbon carbon content and low for mois- 43 tureprooflng agents which are quite soluble or compatible with the other constituents of the coating. Undoubtedly, other factors, such as melting point, solvent composition of the lacquer, type of lacquer base used, choice of plasticizer,

50 etc., also affect this optimum ratio, but the two considerations mentioned above seem to be the more important ones.

A series of experiments, based on the composition of Example IV will, of course, have a pyroxylin lacquer base and a pyroxylin-moistureproofing agent ratio'of 5.26:1. Obviously. h ratio can also be varied and the relations between permeability value and the blending agent-moisture-proofing agent ratio determined for sheets ,60 of regenerated cellulose coatedwith a series of values will be higher for a given blending agent- 70 moistureproofing agent ratio and will eventually pass out of the moistureproof limit. n the other hand, decreasing this ratio (increasing the moistureprooflng agent) does not decrease the permeability values indefinitely and, after a cer- 75 tain point is reached, may even decrease the moistureproofness. Experiments have shown that the optimum lacquer base-moistureprooflng agent ratio usually falls within the limits 1:10 to 200:1 and the blending agent-moistureprooflng agent ratio lies between the limits of 0:1 to 10:1. The most satisfactory cellulose derivative basemoistureproofing lacquers generally fall within these limits for nearly all moistureproofing agents, the optimum pyroxylin-moistureprooflng agent ratios being of the order of 2:1 to 30:1. However, for certain purposes, for example, compositions for casting moistureproof foil, the ratios may differ greatly from those given above and we do not intend that we should be confined to these limits which are suggested merely as an aid to the proper formulation of moistureprooflng lacquers.

The above or any other method for determining the most satisfactory formula in which to use any moistureprooflng agent to achieve minimum. permeability and maximum clarity of coatingmay be used. The above discussion is merely given as one systematic method, whereby compositions may be formulated with the moistureproofing agents here disclosed. Different moistureprooh ing agents will yield different data on such a series of experiments as this, and moisture'prooflng agents of different chemical constitution will be formulated differently into various dopes or vehicles. There is thus no single composition such as has been described above which is capable of universal application. The specific examples hereafter given are thus illustrative, and the above-described method of systematically varying the compositions of solids in which'a mom-- tureprooflng agent is used is exemplary of a general method, whereby optimum results may be. achieved with an agent. The method is, of course, capable of extension to include variations of any of the solid lacquer ingredients, or 40 even to include solvents and the solvent composition. Thus, when one skilled in the art is taught by these disclosures, he will be able to formulate a variety of compositions containing any of the moistureprooflng agents or to determine those compositions with which our moistureproofing agents are most advantageously used. A moistureprooflng agent is thus not a material which will always and universally produce moistureproofcoatings utterly regardless of the composition in which it is used. It usually requires to be formulated in certain favorable compositions to bring out its inherent moistureprooflng properties. On the other hand, a substance which is not inherently moistureproof cannot by any extended amount of work in formulation be made to yield moistureproof films or coatings. Thus, whenwe speak of the inherent property of a compound to moistureproof, we are concerned with a specific inherent property which permits it to be used 30 with some film-forming vehicle to produce moistureproof coatings.

The composition can be used for the production of films, either by casting it in the welllmown manner to produce self-sustaining films, or by coating it on to theselected base. when the composition is to be used as a coating, any

suitable base material, paper, highly calendered paper, glassine, leather fabrics, etc. may be used. The compositions may even be applied to metals to prevent them from rust by virtue of. their moistureprooflng property. They may also be used to coat individual fibers of cotton, wool or artificial silk in such a manner as to make them moistureproof. In the preferred embodiment of the invention, when a transparent wrappin tissue is desired, the base may consist of thinfdense, non-ilbroussubstantially non-porous and preferably transparent sheeting formed of a cellulosic, albuminous or other material. As illustrative examples of cellulosic sheeting may be mentioned cellulosic sheeting coagulated or precipitated from an aqueous dispersion or solution of a cellulosic material, for example, sheeting of regenerated cellulose, glycol cellulose, cellulose glycollic acid, lowly etherified or esterfied cellulose, such as lowly methylated cellulose; and sheeting of cellulose derivatives, such as cellulose acetate, cellulose nitrate, ethyl cellulose, benzyl cellulose. Gelatin and-casein, hardened or not as desired, are mentioned as illustrative examples oi albuminous materials. Sheeting of rubber or rubber derivatives may also be used as the base.

When a selected base, as, for example, regenerated cellulose sheeting, is to be moistureprooied by the compositions hereinbeiore described, the

to use air low in moisture content during the dry ing operation in order to obtain evaporation of the solvent without film blush. Alter being dried, the product, it the base is of the type. which loses moisture at elevated temperatures, 'may be subjected to a humidiiying treatment or other means for a suillcient time to impart or restore flexibility and to deodorize. In some cases. the

lacquer-coatedv materials may be air-dried at room temperature, in which case the humidiiying treatment is not needed.

Hereafter, there are set forth several illustrative specific examples in order to more clear y explain the invention:

I Example I (A) A composition consisting of the iollowlnz ingredients in approximately the proportions set forth is prepared in any convenient and appropriate manner:

A transparent sheet of regenerated cellulose ls submerged in this lacquer which, for convenience,

is maintained at a temperature of 40 C. in or der to prevent separation of the mois u eproonng agent. The excess lacquer is removed by suitable means and the coated sheet is dried, preferably promptly, at an elevated temperature and preferably also in air at 90 C.-1l0 C. The coated sheet is glass-clear in transparency. flexible, non-tacbg, glossy, possesses good surface slip and is only approximately 0.00005" to 0.00015" thi ck- Ethyl lactate er than the uncoated sheet and it is practically impossible to distinguish the coatedsheet from the uncoated sheet in appearance. However, the coated sheet is moistureprooi', having a permeability value of less than 570, for example, of the order of 570 or less.

The coated sheet is much more resistant to the passage of water vapor than a. similar sheet coated with the same lacquer except for the omission of di-octadecyl ether or a sheet coated with a high grade waterproof spar varnish. A sheet coated with the lacquer without the addition of di-octadecyl ether will have a permeability value of 4,000 to 5,000, while the sheet coatedwith a waterprooi spar varnish will have a permeability value of from 2,000 to 4,000.

(B) Dioctadecyl ether in Example I(A) is substituted by an equal amount of dicetyl ether. The process of Example HA) is utilized to coat I the transparent regenerated cellulose sheeting.

The product possesses the same characteristics as the product of Example I(A) except that the product produced by the instant example has a permeability value of theorder of 25 or less.

(C) In Example I(A) substitute an equal amount of lignoceryl phenyl ether for the dioctadecyl ether. The process of Example I(A) is used to coat the transparent regenerated cellulose sheeting. The produc'tpossesses the same'characteristics and properties as that of Example I(A) except that the product produced by the instant example has a permeability value of the order of 570 orless.

Example II A composition consisting of the following ingredients in approximately the proportions set forth is prepared by any. well-known procedure:

Parts by weight Ethyl cellulose -1". 6.0 Rosin 3.6 Tricresyl phosphate 1.0 Dicetyl ether 1.0 Toluene 60.0 Alcoh 19.0 10.0

Transparent sheets of regenerated cellulose are coated and treated in the manner described in Example I(A) The product is transparent, flexible, glossy. has a good surface slip and a permeability value of the order of 200 or less.

Further, compositions of this type may be used for protecting steel and other corrodible metals against rustor the like. The coatings may be air-dried at room temperature for 30 minutes and are times as impermeable to the diffusion of moisture vapors as similar coatings containing no moistureproofing agent.

The omission of ethyl lactate from the above composition will provide a composition suitable for coating. sheets of cellulose acetate and such Example 111 I A composition consisting of the following ingradients in approximately the proportions set forthlspmporedinanywelllmownmanner:

Partsbyweight Ethyl celhrlooe. 7.0 Dlbutyl phthalate. 2.0 Dl-octadecyl'ether 1.0 Toluene 62.0 Alcohol 21.0

a composition consisting of the following ingredients in approximately the proportions set forth is prepared in any well-known manner:

Parts by weight Pyrowii 5.26 Dibntyl phthalate .1 2.82 Di-octadecyl ether 1.00 Ethyl aceta 46.25 Toluene 86.00 Alcohol 6.28 Acetone 0.88

A highly caleridered smooth paper is provided with a continuous layer of this lacquer by coating with or without impregnation, and then dryin: at 90' 02-100" C. The product has a permeability value of the order of 150 or less.

Example V A composition consisting of the followlng'ingradients in approximately the proportions set forth is prepared in any well-known manner: I

Parts by weight era-ted cellulose in the manner described under Example'I, a product is obtained which is glassclear, flexible, non-tacky, glossy, of good surface slip and moistureprooi with a permeability value of 100 or less.

The compositions described in Examples 111 and IV yield coatings which may be slightly hazy. If transparency is essential, a blending agent of the type above mentioned may be incorporated in these compositions. Thus, for example, the lacquer described in Example IV may be so modified that it will always yield a transparent coating by the addition of a blending agent, such as dammar. The quantity of dammar orother blending agent added must be determined as previously described.

The following is an example of a composition wherein a polybasic acid polyhydric alcohol resin constitutes the film-forming ingredient. This composition consisting of the following ingredients in approximately the proportions given is prepared in any suitable manner:

Parts by weight Perilla oil polybasic acid-polyh'ydric alcohol resin varnish 50.0 Di-octadecyl ether 1.0 Toluene 50.0

. The perilla oil polybasic acid-polyhydric alcohol resin varnish is prepared from the following ingredients:

Parts by weight Peril la oil 329.0 Phthalic anhydride; 472.5 Glycerin 204.6 Sodium hydr xi 0.7 Metallic cobalt (added as linoleate) 0.7

Ethyl acetate 800.0

The procedure for preparing the perilla oil polybasic acid-polyhydric alcohol resin varnish is as follows: Heat 72.6'parts of C. P. glycerin to 350 F. in closed kettle-condenser and stirrer. At 350 F. add NaOH, followed by perilla oil. Stir rapidly and heat to 437 F. Hold until clear (-30 minutes). Add phthalic anhydride and heat to 392 F. Add residue of glycerin to batch. Heat to 392 F. and hold (5 hours). Acid number 45-55. Cool to 115? F. Out with ethyl acetate. Add drier and centrifuge. (Solids 50%).

Regenerated cellulose sheeting coated with this composition as explained under Example 1(A) and dried at room temperature or at 90 C.ll0 0. produces a product having a permeability value of the order-of 21-0 or less.-

A. composition of this type may be used without blending agents, but in some cases it is advantageous to use a small amount of a blending agent. Usually, compositions of this nature are suillciently flexible without the addition .of a plasticizer. Lacquers of this type may be used when particularlygood adhesion is desired.

As previously mentioned, another method of obtainingarticles which are of themselves moistureproof is the casting of films containing the organic ethers as moistureprooflng agents. The compositions given in Examples I-IV inclusive may be used for this purpose. It is usually de-- sirable, however, to employ a higher solids base solution for casting sheets than is ordinarily used for forming thin coatings. Furthermore, in

view of the greater thickness of cast foils as a compared to coatings, a smaller proportion of tureproofness, and this in turn will require the use of a smaller quantity of blending agent and/or the use of blending agents other than hard gums in appreciable quantities. Those skilled in the art will be able to formulate by tests satisfactory compositions for the preparation of cast sheets.

The cast sheets and protective coatings prepared in accordance with the instant invention have the ability to resist the transmission or diffusion of water vapor: to an extent at least 4 times that displayed by sheets of equal thickness-and produced from similar or prior art compositionsformulated without the addition of moistureproofing agents. The value 4 merely sets forth theminimum improvement and does not limit the higher moistureproofness that can be obtained. The moistureproofprior art films produced from compositions formulated without the addition of moistureproofing agents not only 4 but 10, 20, 40 and in some cases even fold. This is truly a remarkable accomplishment.

The compounds described in this application as moistureproofing agents have many advantages. Moistureproofing compositions containing the moistureproofing agents are easily duplicated. As previously stated, these compositions in certain formulations thereof yield coatings which air-dry at ordinary temperatures. For certain purposes where it is not feasible to force-dry the coatings, this becomes especially important. As for the moistureproofing agents themselves, they are generally colorless, odorless, tasteless, nonvolatile, and essentially non-toxic, at least in the quantities in which they are used, and they can bereproduced synthetically with a high degree of uniformity and consistency.

In the definition hereinbefore set forth, it is to be understood that the permeability value of 570 represents only the maximum value. In many cases permeabilities of 235, 140, 57, 30 or indeed less may be obtained.

When bases of the preferred type are utilized, the ultimate product is admirably suited for use as a transparent moistureproof wrapping tissue.

Since it is obvious that various changes and modifications may be-made in the above description without departing from the nature or spirit thereof, this invention is not restricted thereto except as set forth in the appended claims.

We claim;

1. An article of manufacture having a continuous unbroken moistureproof surface comprising a film-forming substance and a solid organic ether as the moistureproofing agent, said ether having a melting point of at least37 C. and being a mono-ether containing no modifying groups in the molecule and having at least 18 hydrocarbon carbon atoms for the ether-oxygen .group, said ether being present in an amount to impart moistureproofness to said surface.

2. An article of manufacture comprising a continuous unbroken moistureproof film comprising a film-forming substance and a solid organic ether as the moistureproofing agent, said ether having a melting point of at least 37 C. and being a mono-ether containing no modifying groups in the'molecule and having at least 18 hydrocarbon carbon atoms for the ether-oxygen group, said ether .being present in an amount to impart moistureproofness to said film.

3. An article of manufacture comprising a continuous unbroken moistureproof film comprising a film-forming substance, a solid organic other as the moistureproofing agent, and a blending agent, the ratio of the quantity of film-forming substance to the quantity of ether being within the limits of 1:10' to 200:1, and the ratio of' the quantity of blending ,agent to the quantity of ether being within the limits of 0:1 to 10:1, said ether having a melting point of at least 37 C. and being a mono-ether containing no modifying groups in the moleculev and having at least 18 hydrocarbon carbon atoms for the ether-oxygen group, said ether being present in an amount to impart moistureproofnessto said film.

4. An article of manufacture comprising a continuous unbroken moistureproof film comprising pyroxylin, a solid organic ether as the moistureproofing agent, and a blending agent, the ratio of the quantity of pyroxylin to the quantity of other bein within the limits of 2:1

to 30:1, said ether having a melting point of at least 37 C. and being a mono-ether containing no modifying groups in the molecule and having at least 18 hydrocarbon carbon atoms for the ether-oxygen group, said other being present in an amount to impart moistureproofness to said film. I 5. An article of manufacture comprising a continuous unbroken moistureproof film comprising a film-forming substance and di-octadecyl ether as the moistureproofing agent, the said ether being present in an amount to impart moistureproofness to said film.

6. An article of manufacture comprising a continuous unbroken moistureproof film comprising a film-forming substance and dicetyl other as the moistureproofing agent, the said ether being present in an amount toimpart moistureproof- .ness to said film.

7. An article of manufacture comprising a continuous unbroken moistureproof film comprising a film-forming substance and di-beta-napthyl other as the moistureprooflng agent, the said ether being present in an amount to impart moistureproofness to said film.

8. An article of manufacture comprising a base having a continuous moistureproof coating comprising a film-forming substance and asolid organic ether as the moistureproofing agent, said ether having a melting point of at least 37 C. and being a mono-ether containing no modifying groups in the molecule and having at least 18 hydrocarbon carbon atoms for the ether-oxygen group, said ether being present in an amount to impart moistureproofness to the coating.

9. An article of manufacture comprising a transparent base having a continuous moisture-- proof transparent coating comprising a filmforming substance and a solid organic ether as the moistureproofing agent, said ether having a melting point of at least 37 C. and being a monoether containing no modifying groups in the molecule and having at least 18 hydrocarbon carbon atoms for the ether-oxygen group, said ether being present in an amount to impart moistureproofness to the coating.

10. An article of manufacture comprising a transparent non-fibrous base sheet or film having a continuous moistureproof transparent coating comprising a film-forming substance and a solid organic ether as the moistureproofing agent, said ether having a melting point of at least 3'? C. and being a mono-ether containing no modifying groups in the molecule and having at least 18 hydrocarbon carbon atoms for the ether-oxygen group, said ether being present in an amount to impart moistureproofness to'the coating.

11. An article of manufacture comprising a transparent regenerated cellulose base sheet or film having a continuous moistureproof transparent coating comprising a film-forming substance and a solid organic ether as the moistureproofing agent, said ether having a melting point of at least 37 C. and being a mono-ether containing no modifying groups in the molecule and having at least 18 hydrocarbon carbon atoms for the ether-oxygen group, said ether being present in an amount to impart moistureproofness to the coating.

12. An article of manufacture comprising-a transparent regenerated cellulose base sheet or filmhaving a continuous moistureproof transparent coating comprising a film-forming substance and di-octadecyl ether as the moisture- "It transparent regenerated cellulose base sheet or film having a. continuous moistureprooi' transparent coating comprising a, film-forming sub-. stance'snd dicetyl ether as the moistureprooiing .sgent. said ether being present in an amount to impart moistureproofness to the coating.

14 M article of manufacture comprising a.

V 7 trsnspeient regenerated cellulose base sheet or him having a continuous moistureproof transparent coating comprising a film-forming substance snd di-beta-naphthyl ether as the moistureprooflngsgent, said ether being present'in' an amount to impsrt moistureproofness to the eontin8.

mum HALE CHARCH. MERLIN MAR'IIN BRUBAKER. FREDERICK M. MEIGS. 

